X-ray tube



May 24, 1938.

M. J. GROSS El AL X-RAY TUBE Filed March 16, 1954 2 Sheets-Sheet l up mp I.

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ch ch INVENTOZQ' AT ORNEY May 24, 1938. M. J. GRc-ss ET AL X-RAY TUBE Filed March 16, 1954 2' Sheets-Sheet 2 ll/mum INVENTOg AT ORNEY Patented May 24, 1938 UNITED STATES.

PATENT OFFEE 2,118,434 X-RAY TUBE Application March 16, 1934, Serial No. 715,902

12 Claims.

The present invention has to do with 'an X-ray tube casing that affords both X-ray and electrical protection to the operator and patient, and relates particularly to structural features reducing the size of such casing and affording means of cooling the anode and the glass walls of the tube through the use of a single body of oil.

In such a tube, there is continual circulation of oil, hence there is no possibility of the destructive heating thereof. A tube of large capacity may thus be used in a relatively small casing with no sacrifice in electrical insulation. Such an arrangement as is herein illustrated and described provides maximum protection against tube breakdown, the means for preventing tube puncture being a distinct advance in the art. No previously designed tube has ever possessed facilities of equal merit for connecting high tension conduits to the tube. There are numerous refinements in tube structure which are later fully described.

Included in the objects of the invention are the following:

An X-ray tube casing of relatively small physical dimensions but which affords complete X-ray and electrical protection irrespective of atmospheric conditions, the casing being of relatively slight weight to permit easy handling.

A device of such character in which an in sulating fluid surrounds and insulates the Voltage carrying parts of the tube from an enclosing casing and affords a means for cooling the anode and glass walls of the tube, the structure being such that a cooling medium may be carried to and from the container in flexible tubing covered with grounded metal sheaths.

A novel means of supporting an X-ray tube in a desired position within a casing of the type described. I

A unique structure for attaching cables to the device and for making electrical conductive connections between the cables and the terminals of an X-ray tube.

An improved arrangement whereby current carrying cables and cooling conduit terminals are placed so as not to interfere with one manipulating the tube and container therefor.

These objects and such other objects as may hereinafter appear are obtained by the novel construction, unique arrangement and improved combination of elements illustrated in the accompanying drawings, hereby made a part of this application, and in which:

Figure 1 is a longitudinal section of a device embodying the subject matter of the invention,

certain parts being in elevation for clarity of illustration;

Figure 2 is a section taken along the line 2-2 of Figure 1;

Figure 3 is a transverse section. taken along the line 3-3 of Figure 1 looking in the direction of the arrows.

Figure l is a fragmentary sectional view of the cathode end of the tube casing;

Figure 5 is a section taken along the line 55 of Figure 1;

Figure 6 is a View taken along the line 6-6 of Figure 4 and looking in the direction of the arrows;

Figure 7 is a fragmentary sectional view of the tube and easing at the anode end; and

Figure 8 is a fragmentary sectional view of the device taken at the line 8-8 of Figure 7.

7 Like reference characters are used to designate similar parts in the drawings and in the description of the invention which follows:

Reference should be had first to Figures 1, 2 and 3 wherein there is shown an X-ray tube It with an anode H and a cathode l2 suitably supported in a glass envelope l3. Said tube has arms l4 and i5 which terminate respectively in a cathode base it and an anode base i'l.

Surrounding the tube it] is a metallic casing 7 consisting of a center part l8, preferably of cast metal and metallic hood members 49 and 2!] attached to the center or sleeve part l8 in any desired fashion, as by means of the bolts 2!. An aperture liia, Figure l, is provided in the lower central part of the central cylindrical part l8. Gaskets 22 may be interposed between opposing surfaces of parts l8, l9 and 20 to form oil tight joints between such parts.

Snugly about the center section 23 of the tube H], which center section is cylindrical and of greater diameter than the arms l4 and i5, is an insulating sleeve 2 which preferably comprises material such as wound paper impregmated with any suitable insulating material, such as a phenol condensationproduct. Surrounding the sleeve 24 and secured thereto by means of an adhesive phenol condensation product or other suitable material is an X-ray protective sleeve 25 of lead and of any desired thickness. When designed for use with an X-ray. tube operating at approximately two hundred kilovolts, the wall thickness of the sleeve 25 is about three-six teenths inch. Such lead cylinder 25 is for the purpose of absorbing direct radiation from the X-ray tube.

An aperture 26 is provided in the cylinder or ill - ter being preferably of Bakelite.

sleeve 25 for the passage of a cone of useful X-rays. Surrounding the cylinder 25 and suitably secured thereto by means of a phenol condensation product varnish or the like is the outer 'part 18 heretofore mentioned. In practice, the center part I8 is produced as a separate unit. The insulating cylinder 2 the lead cylinder 25, and the center part ii! are concentrically arranged 'with respect to each other so that the apertures I81; and 26 aline to form. a window .2? for the passage of the heretofore mentioned useful cone of X-light. Such parts are then firmly secured to each other by means of a suitable adhesive insulating compound. It is necessary to make the joint between the opposing faces of the members I8, 24 and 25 oil tight to prevent leakage of oil between the members and out of the window 21. Mechanical rigidity between the concentrically joined members It, 2 3 and 25 is insured by the use of a plurality of screws 28 and washers 29, one of each being shown in Figure l. A plurality of screws 28 and washers .29 are spaced complementarily about the periphery at each end of the lead cylinder 25. The screws 28 thread into lugs 36] extending inwardly of cylindrical part 18 to draw the washers 29 against opposite ends of the lead cylinder.

The hoods is and 2t carry insulating tubes 3| and 32, respectively, held thereto by means of a suitable cement. By overlapping the outer edges of the insulating cylinder 2d, the tubes 3i and 32 prevent fortuitous discharge of electrical energy from the X-ray tube to the metallic walls of the tube casing, which includes the center section l8 and the hoods l9 and 2%.

When the X-ray tube 50 is inserted into the tube casing, it is arranged therewith so that the focal spot 35 on the anode head 36 is alined axially of the casing window 2i. The base it of the cathode is immovably attached to the side arm I4 of the tube in so that the distance from the focal spot 35 to the outer face of the cathode shield 36a is definitely fixed. Thus the focal spot 35 is fixed with respect to the base it wherefore the tube will become properly oriented within the casing by simply adjusting the base I 6 with respect to a certain indicium not shown) upon the casing.

Attention is now directed particularly to Figure 4 wherein the manner of supporting the cathode end of the tube is illustrated. Each of the conductors 31 leading from the cathode of the tube IE! is passed through a bushing 38, which extends through apertures provided therefor in the end of the base member E6. The inner side of the base member is lined with a layer 39 of lead. Escape of vagrant X-rays axially of the tube is prevented by the said layer of lead. Nuts 40 may be turned onto the inner ends oi the bushings 38 to hold such bushings and the membars 39 of lead to the base member it. In support of the bushings 38 and hence of the cathode end of the tube is an insulating block 4|, the lat- Recesses d2 within the member il contain metal terminal pieces 43 and 43a, which pieces are identical and into which may be slipped a metal lug M as the bushings 38 are inserted thereinto. Each of the lugs 44 remains against the end of its respective bushing 38 where it is held by means of a soldered connection 45 to a conductor 3?. The lugs it are slidably contained within the terminal pieces 43 and 6311 so that electrical contact is had therebetween even though the tube it is moved or strip 51.

slightly toward or away from the insulating member V The insulating block 4! is engaged to a metal shield 46 by means of a screw Supporting the shield member 4-5 is a bracket 38 made of insulating material and held thereto by screw 49. The insulating sleeve 3! to which the bracket 48 is attached by means of members 33 and 3 2 has already been described. Members 33 and 34 are preferably of a dielectric material. Inasmuch as the cylindrical insulating member 3! engages the circular neck of the hood l9, the position of the insulating block il is predetermined transversely of the casing.

Angularly disposed within the upper body of the insulating block ll is a ring-shaped section 50 having an opening 5! therethrough. The opening El is for carrying an end of the cathode conductor cable 52 in the manner later to be described. Lining the opening 5| is a sleeve 54, which is threaded externally and internally at its lower end as indicated at 55 and 56. Sleeve 54 is an electrical conductor and is connected to the terminal post 23 by means of a flexible lead Nuts 59 hold the conductor 5'! in engagement with the terminal post 43. One end of the lead 5'! is held in firm electrical contact with the sleeve 54 by means of nuts 58 screwed upon the threads 55. Complemental nuts 59a and 6!! connect opposite ends of a. flexible lead 6!, respectively, to the terminal post 48a and a terminal post 62.

Engaging the internal threads 56 of the sleeve 54 is an insulating plug 63 having a shouldered passageway 54 therein. A coiled compression spring 65 within the passageway 6 presses between the shoulder of the passageway and the head 65 upon the terminal post 62 to urge such post upwardly axially of the opening 5|. The cup-like metallic member 46 serves as a shield about the conductors 5'! and t! and their respective terminals to prevent electrostatic discharges between those parts and the metal casing about the tube.

Figure 4 shows the conductor cable 52 in cross section. One conductor ii'l comprises the center of the cable 52. About the conductor 6? is an insulating layer 68, then a tubular conductor 69, and a comparatively thick outer layer it of insulating material.

The insulating cylinder 32 provides a support for and means for centering the anode end of the tube with respect to the tube casing. A bracket lilfi, which is made of insulating material, extends between the cylinder 32 and a metallic cup-like shield member Hill, the latter serving in the device similarly to the shield member 65 at the cathode end of the tube. Screw I02 and a pin H33 made of insulating material provide means of attachment of the ends of the bracket lflii to the member 32 at its end. Joined to the base member H, which is attached directly to the anode H, is a U-shaped piece I04. Leg Hi5 of the U-shaped piece HM contains a large central aperture for receiving the butt of the base member I! so as to make agood mechanical support therefor and to be immovable thereon. Anchored in the opposite leg I06 of the piece I04 axially of the tube I0 is a pin I01 slidably contained in an aperture )8 within the shield member lill. A spring we exerts a pressure between the shield member I01. and leg I06 of the U- shaped member I04 to press the tube [0 toward the cathode end of the casing to impinge the electrodes 44 against the bottom of their recesses Ill in the terminal members 43. Inasmuch as the head of the anode is measurably spaced from the cathode end of the tube, the focal spot of the anode will always register with the window 21 axially of the casing when the tube is urged to the limit of the movementtoward the cathode support. Registration of the tube radially of the tube casing is insured because of there being two bushings 38 at the cathode end of the tube for guidance into the recessed member 4|. iation of the tube from standard length is taken care of by the spring I09.

In the upper part of the shield lOl is provided a bushing Ill] of electrical conducting material. Bushing I It! is adapted to receive and make electrical contact with a conductor in the cable H leading to the anode of the tube in a manner later to be described.

The cable H for conducting electrical energy to the anode end of the tube may be similar in all respects to the cable 52 as illustrated in Figures l and '7. The corresponding parts of the two cables 52 and ll are designated by the same reference characters. Inasmuch as only a single conductor is used in connection with the anode, a single conductor cable may be used. As the cable ii is presently employed, the center conductor s1 thereof is allowed to stand idle.

Insulating layer 10 of the cables 52 and H is composed of material that is unaffected by being immersed in oil, the material being such as wound varnished cambric. About the cable layer 1!) is a metallic sheath 12, which may be used for connecting the casing to ground. It will be noted that the two cables 52 and H are led into their respective hoods l9 and 20 in the same manner; hence, the same reference characters will be used to designate the corresponding parts of the device for securing the cables to the casing. A supporting sleeve 13 surrounds each cable at the point of entrance to the casing to avert short bends at those sections of the cables and possible injury thereto. The sleeves 13 may be of various structures, but the preferred embodiment consists of a spiral winding of'heavy steel wire tempered to provide a strong resilient support for the cables. Each cable 52 and H is heavily reinforced with insulating material 14 at the section passing into the casing. The body of insulating material 14 may be wound into shape from a strip of varnished cambric; so that the mid-section will coincide with the entrance to the casing, and the end sections taper each way to approach the diameter of the cable. This arrangement of insulating material provides an insulation gradient so that greater insulation is had where the dielectric stress is the greatest. Mechanically, the bodies of insulating material 14 serve to seal the cables into immovable connection with the casing and to prevent leakage of oil from the casing about the joint.

Castings 15 may be made of electrical conductor material such as metal. Their inner surfaces are tapered to conform to the taper of the insulation 14. At the inner side of each joint is a molded piece 16 of suitable insulating material.

I 16 to their respective hoods l9 and 20 is had by means ,of screws 19.and gasket 80, which is inter- Any var-- posed between opposing surfaces of the casing-and the casting 15, the latter sealing the openings to the hoods against the leakage of oil.

In the preparation of the cable 52 for electrical connection to the cathode of the tube lo, the cable is first skinned down at its inner end so that the conductors 6i and 69 are laid bare, as shown in Figure 4. Conductor 69 is cut shorter than conductor 61. A metallic cuff 8| is then soldered to conductor 69. Sleeve Bl is of a diameter adapting it to fit snugly into the threaded sleeve 54, which lines the opening 5| within the insulating member 4!. The end of the inner conductor 61 is left to project such a distance beyond the end of the cable as to abut against the head of the movable terminal post 62 to displace the post a short distance in opposition to the urge of spring 65 and thereby cause an impinging electrical contact with the head of the post. Displacement of the end of the cable 52 from the respective contacts 54 and 66 is precluded because of the binding connection between that sec-. tion of the cable at the entrance to the casing and the casing. A perspective view of the flexible conductors 5'! and BI is shown in Figure 6. Electrical energy may pass from conductor 61 to the terminal post 62, through flexible lead 6 I, through the binding post 43a, through the corresponding electrode 44 and its filament lead 31 to the filament of the tube. After passing through the filament of the tube the energy has a return path by way of the other filament lead 31, its respective electrode 44 and binding post 43, the lead 51, sleeve 54, the cuff 8|, and the cable conductor 69.

- The anode cable II is prepared at its end within the casing in somewhat the same fashion as has been described in connection with the cable 52. That is, an end portion of the outer layer of insulation 10 is cut away to lay bare a section of the conductor 69 therein. A cuif 82 is then slid over the bared part of the conductor and soldered thereto. The cuff 82 is of such a diameter as to slide into the bushing sleeve lit to make a good electrical connection therewith. Electrical energy may flow to the anode by way of the conductor 69 of cable H, cuff 82, bushing Hi}, the shield member llli, spring I89, U-shaped piece H34, screw 93, block 93 to cooling conduit 88, and thence to the anode.

Within the base I? of the anode is a cup-like member 83 of lead to prevent the passage of vagrant X-rays axially of the tube. Additional means for preventing the passage of X-rays axially of the tube is provided in the form of two rings 84 and 85 of insulating material opaque to X-rays. Preferably the rings $4 and B5 are of a phenol condensation product impregnated with a metallic salt of high atomic weight. Rings 84 and 85 may be held in an abutting position to the ends of the enlarged section 23 of the tube ill by means of split collars 86 adapted to be clamped to the side arms of the tube by means of screws 81. Felt washers 85a are preferably interposed between rings and 85 and the adjacent glass walls of the tube.

Extending axially into the butt of the hollow stem of the anode H are two tubes 88 and 89 for conducting a cooling medium to and from the heated end of the anode. These tubes are preferably made of a non-corrosive metal. The tube denominated 88 is for conducting the cooling medium, which may be oil, inwardly of the anode to discharge such medium against the inner wall thereof, whereas the tube as serves to conduct such discharged medium outwardly thereof. A block 90, shown in Figures 7 and 8, having a passageway 9I therein is attached to an end of the inlet conduit 88 by means of a running nut 92. A set screw 93 provides an anchorage of the block to the U-piece I04, Leading from the end of the passageway 9| opposite to which the tube 83 is connected is a tube 94 of insulating material. A conduit piece 95 is joined to conduit Si by an elbow 95. A petcock member designated generally by the reference character 9'! extends through an aperture 98 in the. upper side of the cylindrical casting I8 where it is joined to a piece 99 having a passageway H5. The passageway in the piece as is connected communicatively to the conduit 95 through the agency of a flexible conduit H5 and a coupling member iII. To prevent the piece 99 from becoming loosened from the casting I8, 2. set screw II 3 may be employed.

Suitably attached to the upper end of the petcock 91 is a hose H9, which leads thereto from a pump (not shown) for forcing the cooling medium into the anode by way of the series of conduits and coupling members just described. The conduit IIB may be made of a ductile material such as block tin to provide flexibility therein permitting movement of the conduit system while making connection with the anode.

All parts of the conduit system including the hose H9 are of materials unafiected by the action of oil. A metallic braid iZfi over the hose H9 may serve as a connection between the tube casing and ground.

An outlet for the oil pumped into the anode and into the casing by way of the hose H9 is provided by a petcock I2I and hose 122. The hose I22 may be covered by a grounded metallic braiding I23. When oil is pumped inwardly of the tube casing through the hose I I 9, the oil will flow successively through the petcock 91, piece 9%, conduits H6, 95 and 94, channel 9| in block 90, through tube 88 into the anode, outwardly of the anode through tube 89 into the shield member IDI, and out of the member IilI into the casing about the tube It. When the casing becomes filled with oil, the petcock IEI and hose I22 provide an avenue of escape for more oil as it is forced into the casing. A pressure gauge i23a may be installed to indicate the pressure of the oil within the casing. The oil, in addition to serving as a cooling medium for the anode, provides a dielectric between the tube and the casing. Lugs 38 projecting inwardly from the two ends of the cylindrical casting I8 are spaced apart so that there is ample space between the upper side of the sleeve 25 and the casing I8 for the oil to circulate from one end of the casing to the other. 7

Depending from the casting I8 about the window 21 is an annular member I24 secured thereto by means of screws I25. From the annular member I24 depends a metal cone 25. Screws I21 provide a means of anchorage of the cone to the annular member I24. Lining the cone I28 is a metal sheet I28, preferably of lead so as to intercept X-rays departing from the cone of useful radiation. A screen I 28 may be placed between the annular member I2 l and the body of the cylindrical casing at the window 2'! to cut down, limit or restrict the rays passing therethrough and outwardly of the cone member 25.

Because of the various parts of lead embodied in the tube casing and the parts 39 and 83, which are of lead, at the ends of the side arms of the tube, none but the useful bundle of X-rays can escape from the casing. Moreover, the tube ID is protected against electrical discharges that might otherwise cause a puncture in the glass envelope thereof. Such electrical protection of the tube is had because of its being completely surrounded by a metallic sheath insulated therefrom and carried at ground potential. By filling the casing with an insulating oil, the clearances necessary between the current carrying parts and the walls of the casing are materially reduced, thus providing that the casing need be of but relatively small volume and weight.

An X-ray tube encased in the manner herein illustrated and described is capable of withstanding extremely high loading for the anode is cooled.

by a continuous stream of cool oil forced through it under pressure. Inasmuch as the oil flows through the casing, the latter is continuously flushed and the oil therein is constantly moving so that no foreign matter can collect to form an electrical conductive path between the glass envelo-pe of the tube and the casing.

The manner in which a tube is alined with certainty within the casing has already been described. This makes replacement of a tube, in the event of its being impaired, a comparatively simple operation that may be performed by the person operating the tube. All connections of conductors to the tube are readily detachable to lighten the task of removing a tube from the easing. Cables 52 and H are covered with insulating material that is unaffected by oil so that such cables may be immersed in the oil within the casing whenconnected electrically to the electrodes of the tube and thus obviate the necessity of providing an oil-proof connection extending into the oil and making the joint between the connection and the cable in air which would increase its dimensions materially. Whether the cables are immersed or whether they are simply surrounded by an air space within the casing, a length of the insulation thereon must lie between that section of the cable passing through the wall of the metal casing and the end thereof where the conductors are bared for connection with an electrode of the tube. This intermediate section of insulation prevents creepage of electrical energy between the bared end sections of the conductors and the casing. If the insulation is such that it may be submerged in the oil, the length of insulation betweenthe bared conductors and the wall of the casing may be disposed beneath the oil so that such wall may be carried inwardly to the surface of the oil thereby reducing the size of thecasing.

What is claimed as new and is desired to be secured by Letters Patent of the United States is:

1. An X-ray tube, a casing having Walls of metal provided with a ground connection and enclosing said tube, oil insulation in said casing, cylindrical members within the body of such oil and of insulating material with overlapping ends disposed axially of the tube, and an insulating support'at each end of said tube and engaging the adjacent cylindrical member.

2. An X-ray tube, a casing for containing said X-ray tube and having a ground connection, oil insulation in said casing, there being a central casing member and end casing members at either end of said central member in intercommunicative relation, means for detachably connecting said casing members one to another, and sleeves of insulating material arranged about and extending axially of such tube a distance substantially coextensive with the overall length of said tube, each sleeve having an end section overlapping the end section of the next adjacent sleeve.

3. X-ray apparatus comprising an X-ray tube having a cathode and an anode provided with a face, a base upon the cathode end of said tube at a predetermined distance longitudinally of said tube from the face of said anode, cathode terminals projecting side by side from such end of the tube and beyond said base, a casing for said tube and having a window therein for the passage of X-rays from the face of said anode, there being oil insulation in said casing between said casing and said tube, and said casing having a ground connection, an insulating member in said casing at a distance from such window corresponding longitudinally to the distance between said base and the face of the anode of said tube, connecting sockets in said insulating member and cooperating with said cathode terminals for supporting the capped end of said tube and providing con-- nections to said terminals, said insulating member providing an abutment for said cap to position the tube longitudinally of said casing, a single conductor cable and a multiple conductor cable extending into said casing, means in said insulating member for anchoring said multiple conductor cable, and electrical conductor members leading from the conductors in said multiple conductor cable to the connecting socket in said insulating member, said connecting sockets making connection with said terminals in a manner topermit of said tube being readily withdrawn from said insulating member and cooperating with said terminals to orientate said tube radially in said casing, and said conductor cables having insulation shaped for providing the proper potential gradient between the conductors in said cable and said grounded casing.

4. X-ray apparatus comprising an X-ray tube, a metal casing having a ground connection and enclosing said tube, said casing containing oil for insulating said tube therefrom, there being cable receiving apertures in said casing, high tension cable conductors having an insulating covering extending to adjacent their ends, the end of each cable being free irominsulation and the covered section of each cable extending into said casing through one of the apertures therein, an electrical connection between the uncovered end of each conductor cable and said tube within the body of the oil in said casing, one section of the insulating covering upon the inwardly projecting portion of each cable conductor also being immersed in such oil, and an insulator in the shape of truncated cones joined base to base about each of said cables where it passes through such aperture to provide a proper potential gradient between the-high tension conductor therein and the grounded tube casing.

5. X-ray apparatus comprising an X-ray tube having an anode and a cathode, a casing therefor, there being oil insulation between said casing and said tube and said casing having a ground connection, cathode terminals pojecting from the cathode end of said tube, insulating members in said casing for supporting said tube at each end, a single conductor and a multiple conductor cable extending into said casing to conduct electrical energy to said X-ray tube, means attached to said insulating support members for anchoring said multiple cables in position relative to said X-ray tube, conductor members between said cathode terminals and the conductors in said multiple conductor cable, said conductor members having contacts engaging said cathode terminals to permit of said tube being withdrawn from said support member and positioning said tube radially while in said casing, said anchoring means at the anode end of said tube connecting said anode to the conductor in said single conductor cable, and each of said cables having insulation shaped thereabout within said casing in the form of truncated cones joined base to base to provide a proper potential gradient between the conductors in said cables and said grounded casing.

6. The combination, with an X-ray tube, of means for protecting the tube against fortuitous discharge of electrical energy, comprising a container having metallic walls adapted to enclose a body of insulating oil and provided with a ground connection, a cover for said tube Within said container comprising a solid dielectric ma- 7 terial immersed in the insulating oil within said container, and means within sad cover for supporting said tube, said X-ray tube comprising an anode and a cathode with anode and cathode connections respectively at the opposite ends thereof, said container being formed with de mountable end portions each containing support means for the support of a bushing, a bushing on each of said support means, said bushing comprising a cable embodying a central conductor and a cylindrical sleeve-like conductor about the central conductor and insulation between and surrounding said conductors, the bushing support embodying a pair of cooperating conical sleeves through which the cable extends, said cable having a, wrapping thereon Within said conical sleeves and adapted to be compressed by and between the sleeves when the same are assembled in place whereby to provide a fluid-tight seal at the point of entrance of the cable into the container, and means to connect the cylindrical conductor of one cable with the anode connection of said tube and to connect both conductors of the other cable respectively with the cathode connections.

'7. The combination, with an X-ray tube, of

means for protecting the tube against fortuitous discharge of electrical energy, comprising a container having metallic walls adapted to enclose a body of insulating oil and provided with a ground connection, a cover for said tube within said container comprising a solid dielectric material immersed in the insulating oil within said container, and means within said cover for supporting said tube, the container comprising sections including a central tubular section and removable end sections, the X-ray tube being readily removable from the container upon the removal of an end section, said cover embodying portions mounted respectively on and within said end sections and carrying the insulating means for supporting the opposed ends of the tube.

8. The combination, with an X-ray tube, of means for protecting the tube against fortuitous discharge of electrical energy, comprising a container having metallic walls adapted to enclose a body of insulating oil and provided with a ground connection, a cover for said tube within said container comprising a solid dielectric material immersed in the insulating oil within said container, and means within said cover for supporting said tube, said container comprising a central tubular portion and removable end portions and said cover comprising an insulating sleeve carried by and within the tubular central portion of the container, and sleeve-like elements carried by and'within the removable end portions of the container and having ends projecting within the central tubular portion of the container in position to encircle the opposite ends of the insulating sleeve carried thereby.

9. The combination, with an X-ray tube, of means for protecting the tube against fortuitous discharge of electrical energy, comprising a container having metallic walls adapted to enclose a body of insulating oil and provided with a ground connection, a cover for said tube within said container comprising a solid dielectric material immersed in the insulating oil within said container, and means within said cover for sup porting said tube, said container comprising a central tubular portion and removable end portions and said cover comprising an insulating sleeve carried by and within the tubular central portion of the container, sleeve-like elements carried by and within the removable end portions of the container and having ends projecting within the central tubular portion of the container in position to encircle the opposite ends of the insulating sleeve carried thereby, said insulating means for supporting the tube comprising clamping collars within said insulating sleeve for securing the central portions of the tube in place therein, and brackets on said sleeve-like elements for receiving the opposed ends of the X-ray tube.

10. The combination, with an X-ray tube, of means'ior protecting the tube against fortuitous discharge of electrical energy, comprising a container having metallic walls adapted to enclose a body of insulating oil and provided with a ground connection, a cover for said tube within said container comprising a solid dielectric ,material immersed in the insulating oil within said container, and means within said cover for supporting said tube, said container comprising a central tubular portion and removable end portions and said cover comprising an insulating sleeve carried by and within the tubular central portion of the container, sleeve-like elements carried by and within the removable end portions of the container and having ends projecting within the central tubular portion of the container in position to encircle the opposite ends of the insulating sleeve carried thereby, said insulating means for supporting the tube comprising clamping collars within said insulating sleeve for securing the central portions of the tube in place therein, brackets on said sleevelike elements for receiving the opposed ends of the X-ray tube, the central portion of said container providing a window and said tube embodying an anode, one of said brackets being positioned at a predetermined distance from said window to register the anode with said window when the tube is mounted in said bracket, and

yielding means on the other bracket for normally urging the tube longitudinally in order to maintain the anode in registration with the window.

11. The combination, with an X-ray tube, of means for protecting the tube against fortuitous discharge of electrical energy, comprising a container having metallic walls adapted to enclose a body of insulating oil and provided with a ground connection, a cover for said tube within said container comprising a solid dielectric material immersed in the insulating oil within said container, and means within said cover for supporting said tube,'the container comprising a central tubular portion'and removable end portions of identical construction, bushings of substantially identical construction on said end portions and embodying each a cable comprising a central conductor and a sleeve-like conductor about the central conductor and insulated therefrom, and an end support bracket for said tube in each of said end portions of the container and supported by the insulating means, the conductors of one cable being connected with terminals of one of said brackets and the sleeve-like conductor of the other cable being electrically connected with a terminal on the other bracket whereby the tube may be assembled in or dismounted from the container by merely removing one of the end portions thereof.

12. The combination, with an X-ray tube, of means for protecting the tube against fortuitous discharge of electrical energy, comprising a container having metallic walls adapted to enclose a body of insulating oil and provided with a ground connection, a cover for said tube within said container comprising a solid dielectric material immersed in the insulating oil within said container, and means within said cover for supporting said tube, the container comprising a central tubular portion and removable end portions of identical construction, bushings of substantially identical construction'on said end portions and embodying each a cable comprising a central conductor and a sleeve-like conductor about the central conductor and insulated therefrom, an end support bracket for said tube in each of said end portions of the container and supported by the insulating means, the conductors of one cable being connected with terminals of one of said brackets and the sleeve-like conductor of the other cable being electrically connected with a terminal on the other bracket whereby the tube may be assembled in or dismounted from the container by merely removing one of the end portions thereof, and means supported on the central tubular portion of the container for circulating insulating oil into and out of the container.

lVLALVE-RN J. GROSS. ZED J. ATLEE. 

